DNA

• DNA is made of nucleotides
• DNA strands are made of polymers. they are made of repeating units joined together. they are made of repeating units joined together. Each unit is called the nucleotide
• Each nucleotide is made of a sugar , a phosphate group , and a base
• the four different bases are called adenine, thymine, cytosine, and guanine.
• one of the four different bases join to each sugar
• a dna strand has two strands coiled together which forms a double helix
• Each base links to a base on the opposite strand (AT,CG). this is called complementary base pairing. the complementary base pairs are joined by weak hydrogen bonds
• DNA is stored as chromosomes
• chromosomes are long coiled up lengths of DNA molecules
• a gene is a section of DNA on a chromosome
• each gene codes for a particular protein
• the order of bases in a gene decides what protein is made
• an organisms genome is all of its DNA